SparkFun Forums

[riki]

I have been using ftdi's usb to rs232 bridge - i have several and am constantly having to change the com port for different applications i.e. going into control panel on the pc and going through several menuses until i click on 'advanced' and then am able to change the com port.
Is there an easier way?

[andrey]

I had the same problem. There's no way to get around it but you can do some tricks in your software (assuming you wrote a program for the PC that talks to your embedded project) to help. Instead of providing a menu with com ports to try, have the software first look at all available com ports and send some special message to each one. Have the emdedded system, upon getting such a message, reply to the pc software in some defined way. This way the PC software can find all of the instances of the embedded system that are plugged in without the user having to guess where they might be. Kind of a 'plug and play' approach.

[riki]

Yes, there is no problem for PC software written by myself. I use Delphi and 'PortController' for VCP comms- In the 'Read portcontroller' port function a variable can be included to perform a time-out, and if using FTDI's DLL then there is a simple time-out function if port data is not available.

There are other functions to test for an open port. either VCP or DLL.

The problem arises from commercial software. For example I have several GPS diagnostics to test the Lassen GPS module.Some have a 'select COM port' menu, others don't. So old problem have to go to control panel, system,device manager to see what port and change it if required.

Looks like Microsoft got it wrong since there is no easy way to interrogate and change the COMport.Of course not having any 'old' RS232 COM ports on all new PC's/Laptops doesn't help and I have to continually resort to USB/RS232 bridges and virtual ports.

'SerialWatcher' is a simple terminal program (From port to PC) was easy enuf to test which port is being used but no way to change the COM port of the PC.
Methinks this is an unsoluble problem,
BRING BACK THE RS232 PORT!
or maybe just like the old BBC microcomputer have an 8-bit user port sticking out of the PC (optically-isolated of course) connected to the system bus! ha ha

Regards,Riki

[andrey]

Hmm... that is easier in Linux but in general I think you're right, it's just a problem with USB and how USB 'com ports' are managed

[Philba]

I run into this all the time since I have a number of devices that I control via a "serial HUB" (serial over ethernet). I've got like 14 com ports (all but 2 virtual) and have to constantly switch them in the control panel because old software is inflexible about com ports.

I'm thinking I need to write a program that allows quick switching of the com numbers but there are just too many projects.